Pumps capable of operating at extremely high pressures, namely, pressures in the range of 10,000 to 40,000 PSI have become an important facet in a number of industries. One industry includes water blasting wherein water is jettisoned from a small orifice nozzle at pressures in the range of 10,000 to 40,000 PSI and at a sufficient gallonage rate to effect a literal blasting of water against a surface for purposes of cleaning it and even including eroding it. Oftentimes, the nozzle arrangement is embodied in a hand gun with appropriate valving on the hand gun for facilitating fluid flow through the valve as well as halting fluid flow through the valve. When high fluid pressures are being utilized, extreme care must be taken to assure that when the hand held valve is turned OFF, the fluid within the conduit leading to the valve on the hand gun be appropriately vented so as to prevent a bursting of the conduit or valve body. Heretofore, conduits with pressures in the range of 10,000 to 40,000 PSI therein have required a dump or shut off gun to be utilized, namely, a hand held lance-gun having a dump or shut off flow feature associated therewith which causes fluid to be diverted to the atmosphere at a very low velocity immediately upon the closing of the valve to halt fluid flow to the nozzle. One of the drawbacks in this type of arrangement is, while in the dump mode, excessive water from the gun dump port is spilled into the work environment increasing liquid contaminant clean up and disposal requirements. In addition, when the shut off gun is used, the conduit extending between the pump and the hand gun still has the high pressure fluid contained therein, namely, fluid at a pressure of 10,000 to 40,000 PSI. If the conduit should be pierced, such as might happen when a vehicle runs over the conduit, there is the danger that the conduit will become violently manipulated by the exiting high pressure fluid to cause injury to personnel and/or equipment located within the region.
Accordingly, it is an object of this invention to provide a remote pressure sensitive dump valve that is adapted to be connected directly to the outlet port from a high pressure pump and to enable the use of hand held guns which are free of the provision of any auxiliary dump valve diverting blocked fluid flow to the atmosphere.
It is a further object of the invention to provide a remote pressure sensitive dump valve, as aforesaid, which when dumping the fluid flow from the pump in response to a closing of a hand held gun, the pressure in the conduit extending from the outlet of the dump valve to the gun is at a low pressure thereby minimizing the likelihood of injury to personal and/or damage to equipment located close by should the conduit be inadvertently severed.
It is a further object of the invention to provide a remote pressure sensitive dump valve, as aforesaid, wherein a dumping of the high pressure fluid (liquid) to atmosphere is hydraulically assured promptly upon the occurrence of a halting of the fluid flow through the dump valve to thereby prevent damage to the hose and/or hand gun.
It is a further object of the invention to provide a remote pressure sensitive dump valve, as aforesaid, wherein the dump valve is comprised of a minimum number of component parts thereby making the durability thereof and the maintenance thereof simple and easy.
It is a further object of the invention to provide a remote pressure sensitive dump valve, as aforesaid, wherein the pressure at which the dump valve is activated in controllable by the provision of at least one replaceable orifice plug in an end of a shiftable valve member remote from the fluid supply port on the dump valve and through which the fluid deliverable to the hand held gun must flow in order to assure a proper control movement of the valve member relative to a valve seat provided in the dump valve.
It is a further object of the invention to provide a remote pressure sensitive dump valve, as aforesaid, wherein a further replaceable orifice plug is provided in a return conduit into which fluid, here liquid, is dumped when the valve or the hand gun is closed, the cross-sectional area of the orifice in the further orifice plug is the same as the orifice in the orifice plug oriented on the valve member.